OOAD-设计模式-命令模式

 命令模式由三上角色构成

命令对象：将接收放注入到内部由它来构建一条命令，在内部有命令的执行的行为，

命令的接收方：负责接收外部的命令

请求命令，命令的发送方：将构建成功的命令对象注入，可执行不同的命令。在内部有请求执行命令的行为

下面是一个小例子：

package com.lovo.test;

 

public abstract class Command {

 

 protected Receiverable receiver;

 

 public Command(Receiverable receiver) {

  this.receiver = receiver;

 }

 public abstract void execute();

}

 

package com.lovo.test;

 

public class CommandImpl extends Command {

 public CommandImpl(Receiverable receiver) {

  super(receiver);

 }

 public void execute() {

  receiver.receive();

 }

}

 

package com.lovo.test;

 

public interface Receiverable {

 public void receive();

}

 

package com.lovo.test;

 

public class Receiver implements Receiverable {

 @Override

 public void receive() {

  System.out.println("This is Receive class!");

 }

}

 

package com.lovo.test;

 

public class Invoker {

 

 private Command command;

 // 使用set注入

 public void setCommand(Command command) {

  this.command = command;

 }

 public void execute() {

  command.execute();

 }

}

 

package com.lovo.test;

 

public class OpenGun implements Receiverable {

 @Override

 public void receive() {

  // TODO Auto-generated method stub

  System.out.println("向敌人开火");

 }

}

 

package com.lovo.test;

 

public class Test {

 public static void main(String[] args) {

  Receiver rec = new Receiver();

  OpenGun og = new OpenGun(); // 命令的接收方，负责将接收到命令

  GoJapan gj = new GoJapan();

  Command cmd = new CommandImpl(gj); // 将命令的接收方传入命令对象中，构建一条命令

  Invoker i = new Invoker(); // 请求执行此命令，请求的发出方

  i.setCommand(cmd);

  i.execute(); // 执行命令

 }

}